This is the connector I touch to start charging
I have a 1973 Ranchero GT with the 351 Q code engine with the C6 automatic transmission. I am having a problem with the charging system. While driving the charge light will come on and through trial and error I have discovered that when the light is on the battery is getting no charge from the alternator, I read 12.3 volts with an ohmmeter. When the light is off the battery is getting 14.4 volts from the alternator. I can make this change happen just by touching the connector shown in the picture below that I am pointing at. I have the high output 90 amp alternator and I had the alternator checked off the car and it put out 80 amps on the test stand at the Oreilleys here. I was wondering if this means I should l just replace the alternator with a rebuilt one or can I replace the part inside the alternator that connects to the two blades. I have replaced the connector with one that was supposed to be for the high output alternator from Dorman but it again is not an exact duplicate of the one that was on the car but the one on the car was very rusty on the contacts and I am sure was not making good contact. Thanks for your thoughts on this issue.

 

If you think that connection is loose or worn, then I would have it replaced. Any starter/generator shop should be able to do it for a few bucks. If you think your skills are sufficient and you can find the part, go for it. The hard part will probably be, finding the part.

 

Pic: Type the basic part number of the part you need.

Q = 351C 4V GT

 

Thanks for the help. I can see from the drawing that the piece I am pushing on is the holder for the brushes part number 10347 so it makes some sense now that if the brushes are worn then pressing on the holder could help to make contact. Number Dummy is this part still available? Thanks again for your help. I do hope to have all these little issues worked out and so I can start to work on the body.

 

That brush holder assembly should be available aftermarket about anywhere. Here's a link to Rock Auto that shows a photo.

https://www.rockauto.com/en/catalog/...sh+holder,2420

 

D2OZ-10347-B .. Brush Set (Motorcraft GB-128-B) / Obsoleted recently

70/90/100 amp alternators.

HAVEN FORD PARTS in Haven KS has 2 = 620-465-2252.

GREEN SALES CO. in Cincinnati OH has 14 = 800-543-4959.

Just wait until you dig into the body work, because Ranchero's are notorious for rusting from the inside out.

 

Well thanks for the warning Number Dummy but this is an Arizona car for all its life and hope that what i see on the lower door corners and some in the bed is all there is. I hope!!! Thanks for the information to all that have helped and will look for the brush holder this weekend and try to rebuild the alternator. I have done some alternators in the past but never a 90 amp high output. This is a wonderful resource here for help when I am struck.

 

AZ makes no difference. What most people that own a Ranchero don't know is that underneath the Ranchero's bed pan is the station wagon floor pan that contains rear seat and foot wells and the spare tire well.

Ford spot welded the bed pan in place, then used flexible caulk to fill in the gaps. The caulk hardens, chips off, water seeps in and has no place to go because there aren't any drain holes.

So rust begins and it's hidden from view, so don't be surprised if when headin' down the road that the gas tank falls off, because above it is the spare tire well.

I know two people that this happened to, one had a '57 another had a '72. Both 1957/59 & 1972/79 have body on frame construction.

1960/71's are unit bodies, and when these rust...be prepared to spend a bundle fixing it.

 

Well it is fixed thanks for the help. Then problem was both of the screws holding in the brush holder had loosened up just a little. Had new brush holder with brushes so installed it and it now puts of more voltage at 14.45 up from14.3 before.
As far as rust I see some on the bed but it sounds solid so I will just keep checking. Is there any thing that can help prevent it if I find not much rust? Thanks

 

Hi,
I would think you could minimize floor pan rust by drilling some drain holes in the lowest parts of the station wagon floor pan. It would be nice to find someone on this forum who knows exactly where the most rust-prone areas are. Even when washing your car, some water might work its way underneath where it will sit and cause rust.

I'm glad to see you were able to get your alternator working correctly again.

Regards, Tom